[10/15] Abstract i386_dr_low access

diff --git a/gdb/gdbserver/i386-low.c b/gdb/gdbserver/i386-low.c
index 8c50838..8d6f26c 100644
--- a/gdb/gdbserver/i386-low.c
+++ b/gdb/gdbserver/i386-low.c
@@ -32,6 +32,9 @@ 
    The functions below implement debug registers sharing by reference
    counts, and allow to watch regions up to 16 bytes long.  */
 
+#define i386_dr_low_can_set_addr() 1
+#define i386_dr_low_can_set_control() 1
+
 /* Debug register size, in bytes.  */
 /* NOTE: sizeof (long) == 4 on win64.  */
 #define i386_get_debug_register_length() (sizeof (void *))
@@ -273,6 +276,9 @@  i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
 {
   int i;
 
+  if (!i386_dr_low_can_set_addr () || !i386_dr_low_can_set_control ())
+    return -1;
+
   /* First, look for an occupied debug register with the same address
      and the same RW and LEN definitions.  If we find one, we can
      reuse it for this watchpoint as well (and save a register).  */
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c
index a64cdab..4282535 100644
--- a/gdb/i386-nat.c
+++ b/gdb/i386-nat.c
@@ -47,6 +47,19 @@  static int debug_hw_points;
 /* Low-level function vector.  */
 struct i386_dr_low_type i386_dr_low;
 
+#define i386_dr_low_can_set_addr() (i386_dr_low.set_addr != NULL)
+#define i386_dr_low_can_set_control() (i386_dr_low.set_control != NULL)
+
+#define i386_dr_low_set_addr(new_state, i) \
+  (i386_dr_low.set_addr ((i), (new_state)->dr_mirror[(i)]))
+
+#define i386_dr_low_set_control(new_state) \
+  (i386_dr_low.set_control ((new_state)->dr_control_mirror))
+
+#define i386_dr_low_get_addr(i) (i386_dr_low.get_addr ((i)))
+#define i386_dr_low_get_status() (i386_dr_low.get_status ())
+#define i386_dr_low_get_control() (i386_dr_low.get_control ())
+
 /* Debug register size, in bytes.  */
 #define i386_get_debug_register_length() \
   (i386_dr_low.debug_register_length)
@@ -379,7 +392,7 @@  i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
 {
   int i;
 
-  if (!i386_dr_low.set_addr || !i386_dr_low.set_control)
+  if (!i386_dr_low_can_set_addr () || !i386_dr_low_can_set_control ())
     return -1;
 
   /* First, look for an occupied debug register with the same address
@@ -538,13 +551,13 @@  i386_update_inferior_debug_regs (struct i386_debug_reg_state *state,
   ALL_DEBUG_REGISTERS (i)
     {
       if (I386_DR_VACANT (new_state, i) != I386_DR_VACANT (state, i))
-	i386_dr_low.set_addr (i, new_state->dr_mirror[i]);
+	i386_dr_low_set_addr (new_state, i);
       else
 	gdb_assert (new_state->dr_mirror[i] == state->dr_mirror[i]);
     }
 
   if (new_state->dr_control_mirror != state->dr_control_mirror)
-    i386_dr_low.set_control (new_state->dr_control_mirror);
+    i386_dr_low_set_control (new_state);
 
   *state = *new_state;
 }
@@ -698,7 +711,7 @@  i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
      was running when we last changed watchpoints, the mirror no
      longer represents what was set in this thread's debug
      registers.  */
-  status = i386_dr_low.get_status ();
+  status = i386_dr_low_get_status ();
 
   ALL_DEBUG_REGISTERS (i)
     {
@@ -707,7 +720,7 @@  i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
 
       if (!control_p)
 	{
-	  control = i386_dr_low.get_control ();
+	  control = i386_dr_low_get_control ();
 	  control_p = 1;
 	}
 
@@ -718,7 +731,7 @@  i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
 	 paranoiac.  */
       if (I386_DR_GET_RW_LEN (control, i) != 0)
 	{
-	  addr = i386_dr_low.get_addr (i);
+	  addr = i386_dr_low_get_addr (i);
 	  rc = 1;
 	  if (debug_hw_points)
 	    i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write);